Sweetness of sweet protein thaumatin is more thermoresistant under acid conditions than under neutral or alkaline conditions

Citation
R. Kaneko et N. Kitabatake, Sweetness of sweet protein thaumatin is more thermoresistant under acid conditions than under neutral or alkaline conditions, BIOS BIOT B, 65(2), 2001, pp. 409-413
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Agricultural Chemistry","Biochemistry & Biophysics
Journal title
BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY
ISSN journal
0916-8451 → ACNP
Volume
65
Issue
2
Year of publication
2001
Pages
409 - 413
Database
ISI
SICI code
0916-8451(200102)65:2<409:SOSPTI>2.0.ZU;2-A
Abstract
Thermostability of thaumatin and mechanisms of thermoinactivation were exam ined at 80 degreesC in the pH range from 2 to 10. The sweetness of thaumati n disappeared on heating at pH above 7 for 15 min, but the sweetness remain ed even after heating at 80 degreesC for 4 h at pH 2. This indicated that t he sweet protein thaumatin is more thermoresistant under acid conditions th an under neutral or alkaline conditions. Prolonged heating of thaumatin und er acid conditions slowly reduced sweetness, and produced a heterogeneous p opulation of molecules, all of which was soluble and monomeric. The resulta nt molecules were clearly distinct from those generated by heating at pH ab ove 7. Hydrolysis of peptide bonds and other irreversible chemical reaction s slowly took place in the molecule heated under acid conditions, and it wo uld be, in part, a cause of thermoinactivation of thaumatin under acid cond itions. The thermostability of thaumatin and the mechanism of thermoinactiv ation were largely dependent on pH.